That is in Isaiah 62:4. In the context God has said that He would take away our rightful name which is "Forsaken," and would call us by a new name, a name which He would choose. That name will be "Hephzibah." We read, "You will no more be termed Forsaken; neither shall your land any more be termed Desolate: but you shall be called Hephzibah." And again, that word means: 'My delight is in her.'